Sound-reproducer.



, W. A.y CHAPMAN.

`SOUND REPBODUGBB. l APPLICATION FILED 1120.2. 1907.

.Patented octv. 2o,19o8.

WILLIAM. ALeuz/f CHAPMAN, or suiTi-ivncLi;` Annan sas.

soUNnRErRoDUoER.

Specification of Letters Fatt-mt.

rcentes oct. 2o, i908.

Application filed Eecember 2, 1907. Serial No. 404,664.

To all whom it may concern:-

lie it known that l, VVILLAM ALBERT (li-urnas, a citizen of the United States, and a resident of Smithville, in the county oi? Lawrence and State oit' Arkansas, have invented a new and `lmprtwed Sound-Re-` producer, of which the Jfollowing is a full, clear, and exact description.

This invention relates to sound reprodueers, and is particularly useful in connection with talking machines, and more espe cially those employing records of the disk type. l

simple, durable' and etlicient soundreproduccr which constructed to eliminate harsh, shrill and metallic tones in sound reH production, and which exactly reproduces vthe volume, register and tone shading oil the original sound.

A further object of the invention is to provide. a sound reproducer having a diaphragm which is normally under different balanced tensions, thereby augmenting the sensitive ness and rapidity oi? action of the diaphragm.

.i still furil'rer object of the invention is to provide a sound i'eproduccr having a sty-lus har which permits the easy and rapid insertion and removal ot` needle points, and which is resiliently controlled, whereby it is rendered flexible and ellicient in action. l

The invention consists in the construction and combination of parts lto be more fully described hereinafter and particularly set forth in the claims.

Reference is to be had to the aceonipanying drawings forming a part of this speciii; cation, in which similar characters of ire-fel ence indicate corresponding parts in all the views, and in which Figure l is a front elevation of the sound reproducer,Fig. 2 is a longitudinal section. Votthe device; Fig. 3 is an enlarged transverse section on the line 313 of Fig. 2; Fig. e is a transverse section on ltheline #lv/lf of `lFig. 3; and Fig.4 is an enlarged transverse section Ion the line 5-5 of Fig.

lieforeproceeding toa more detailed eX- planation of my invention, it should be understood thatin the sound reproducers hithertoemployed it "as generally attempted by the constructors to provide a reproduit ing diaphragm which was normally under no stress ot any hind; that is, to attain neutrality in the diaphragm. 4lt was believed that a diaphragm ot ,this character An object of the invention is to provide a was particularly sensitive in responding to vexternal forces applied thereto; for instance, the vibrations transmitted to the diaphragm through the stylus arm. I have found that Athe inertia ot' the neutral diaphragm, instead of permitting the instan taneous response of the diaphragm to ex traneous force applied thereto, prevents the able in sound reproducer diaphragmsl but is absolutely essential to their successful operation. Thus, the Ainertia of the diaphragm conduccs 'to the suppressioi'i of delicate tones or sound shadings which are of such importance in the'accurate and tunet'ul reproduction ol`A sound. Certain of the vibratory impulses transmitted to vthe diaphragm and which the latter should reproduce, are so slight and oi such intense rapidity that the neutral diaphragm is quite incapable of propagating them further.' l provide a diaphragm which is normally under opposite and conflicting` tensions, so that in a normal vcondition these stresses are balanced. This dia phragm is rendered particularly sensitive owing' to the balanced tensions to which it is subject, and is responsive lo the slightest and most rapid' ot vib 'atory influences. The diaphragm is under greatest tension at the center,` and the ltension decreases from the center toward the periphery. As the ten ject are in. opposite directions and balance each other, `an impulse from either side of overt-mno that at. the other. The consequence is the instantaneous and positivemetion el the diaphragm to reproduce the sound. The vibrations causing the unbal-r phragin are transmit-ted from the record to the diaphragm by means` of the stylus bar.

The stylus'bar of mysound reproducer is the vibrations :trom the sound record to the diaphragm. butis provided with resilient or hcushion restraining means which serve to limit the movement of thestylus bar. The needle points which are Vused indisk record talking machines to transmit the vibrations replaced at frequent intervals. To permit the needle points tombe attachedto` "ox-"le rapidity of action, vvhichis not only desirthe diaphragm disturbs t-he balance, and p thereby causes thetension at one side to moved from the stylusba'r 03'; my invention,

sion stresses to which the diaphragm is subancing of the tension stresses in the diamounted to rock upon fthereproducer cas- Y ing. lt is free to move inici-der to, transmit from the record to the stylus har, have to be Y hereinafter.

asiliI and rapidly, l provide special needle lmini retaining means .which can be easily and rapidly operated u'ianually.

` itchy/ing more particularly to the draivingsfl represents the casingot the sound ditions. The casing l has an outlet 2, byv

/ineans oll which it can be suitably connected to the sound tube of the talking machine; The casing has a baci: and side walls, being open at the front. A Washer 3, of annular lorin in cross-section, is arranged Within the casing adjacent to the back thereof. The diaphragni ll seats upon the Washer 3a and at the outside oi the diaphragm is arranged a secohd washer 5, similar to the Washer 3. i spliti or spring,r ring 6, is arranged in an annuler recess 7 ol. the casing, and serves to hold the washers and the diaphragm in position within the casing. v

The diaphragm comprises similar opposite faces or disks 8, which may be loi'cined from any si itable material for the purpose, such as mica, or the like. The disks 8 are spaced .nea-r the peripheries by means of an.`

annular block 9. and at the outer Sides have strengthening rings 10, i secured upon the faces thereofnear the periph/cries, in any` convenient manner. The disks@ are secured together near the center in a manner which will appear more clearly hereinafter, and are thus placed under tension. rihe iii-curving of the disks is in opposite directions, and consequently, they are under opposite ten sions which normally balance each other. lt vwill be understood that the annular separa` tor 9 has"the opposite faces beveled to permit the incurring of the disks. The parte oi the diaphragm are securely fastened tov gether so that they constitute a rigid Whole.

At the bottoni et the casinfci` are lugs l1,

lmp-.terribly integral therewith and provided,-

.ivith registering threaded Openings therethrough. Corresponding'ly threaded 'rocker pins l2, are arranged in the openings ot' the lugs and have nuts 13, by means of which they can be locked in position, and/"further 'have tapered for a purpose which Will appear The stylus bar l5, is laterallyv extended and has an opening through the laterally extended portion, in which is rigidly mounted a rocker bar l5". At thc ends' of the latter are formed tapered recesses li adapted to receive the tapered extremities o the rocker pins l2. l By means of the rocker i pins the pivotal mounting oil the stylus bar can be exactly adjusted. A vibrating arm the inwardly proj cctingr extremities ll,

scip/se l?, is rigidly carried by (he stylus bar and is pret'ei'ahl),Y interni-al therewith. 'lhe vibrating' arm may have any suitable .lorui and has the end inwardly disposed' adjacent, suhstantially, to the center oil the diaph ngen. Atthc' end of the vibrating arm l? is secured a tace plate 1S, adapted to rcst adjacent to the diaphragm, and having a tl'ireadcd opening' therethrough formed to receive a corre-- spondingly ihren ded screw l-l, which serves to secure tlic diaphragm to the vibratingr arm and to fasten the opposite disks or plates o t' the diaphragm to each other. Behind the face plate 1S the viln'ating arm has a recess 20, to permit the projection. bevond vthe face plate, of the screw 19. The head of the screw is substantially equal in diameter to the Width of the `face plate, so that the oppositc disks of the diaphragm are held together by contacting surfaces of substantiall)7 equal area.

it the side of the stylus loa-r l5 remote from the vibrating arm. 17, is formed an arm 2l. extending beyond the sound reprodncer casing and having the end provided 'with a split or slot 22. At the top and bottoni of the arm 2l are termed recesses 28, adapted to receive resilient cushions 2d. The latter may be of any preferred orconnnon torni; for instance, shown in the drawings, they may consist of hollow balls of resilient niate'rial, such as rubber. A. U-shaped bracket 25, is mounted upon the casing and extends over the end of the arm`2l, havingreeesses 2li, nori'nally arranged opposite to the corresponding recesses 23 and also serving to receive the cushions 242. lt will he understood that by means ot' the arm 2l, the cushions 2Liaud the bracket 25. the stylus bar is resiliently held in position such that its normal position corresponds to the normal position oit the diaphragm. llifhen the diaphragm is displaced in one direction or the other, the stylus har is'correspondingly displaced and the cushion restraining means of the stylus bar assist the diaphragm in returning to its normal position. ln it is desired. to re the movement of Athe stylus har more strongly, bauds 27 of rubber or the like, can

he arranged in slot or' the arm and' passed over the bracket being held in position by suitable spurs 28 of the latter, as is shown most clearly in Fig. 5.

The stylus har l5 a .longitudinal opening or,I recess adapted to receive the needle @point 30, which may he oil any preferred or common form. A transverse opening 3l, is formed wit-hin the stylus l er and intersects theopening 29. A member 32 .having a notch or recess 33, is movably arranged Within the opening 3l, and by the engagement of the notch 3l with the needle. point, serves to holdlthe latter rinly in po- TilV sition. At one end,`the member 32 has a constricted shank 3a, project-ing through a iso Y 901,782 y i I I .Y constricted opening 35 in the stylus bar. A

each other at a helicalcspring 36, arranged upon the shank 34 holds the member 32 1n a normal, inoperative position. The member 32 which constitutes the needle 'point clamp, has further a constricted end 37 projecting from the opening 3l. A spring ring 38 4is arranged in an annular recess of the opening 31 and serves to retain the member or clamp within the opening. The s liank 34 has a portion 39 of angular section, which isrreceived by a correspondingly formed portrion of the opening 35, and which preventsr il.' rotation .of the member. When it is desired to insert a needle point in positiomgtlie member 32 is moved against the tensionof the spring until the notch 33 is so positioned that the needle point can be assed through it. ing the mem jams the member against the needle point and holds the same in position in the recess 29.

Having thus described my invention, I

` By releas claim as new and desire to secure by Lettersv Patent:

1. In a sound relfnodiicer,y

a diaphragm having opposite,

vibrating faces rigid with point within their periplicries, and an annular spacing member separatn said faces at their peripheries whereby said aces are rendered concave, said meniber having the opposite sides shaped toconform to the curvature of said vibrating faces.

lIn a sound reprodiicer, a diaphragm having opposite, vibrating faces rigidly secured together at a point within their peripheries and in direct engagement at' this point, and an annular spacing member between said faces at the peripheries thereof whereby said faces are oppositely in-curved, said member havingthe opposite sides shaped to coliform to the curvature of said vibrating faces. f

3. In a sound reproducer, a dizqihragin having opposite. vibrating faces fastened together near the centers and in direct engagement `at the point of fastening, and an annular spacing member separating said faces at their peripheries whereby said faces are rendered oppositely concave, said member ,having opposite sides beveled to conform to the coiicavity of said faces.

il. In a sound reproducer, a diaphragm having opposite, vibrating faces part-ly in engagement within the peripheri'esiand partly spaced whereby an airtight chamber is formed therclwtweeniyand an annular menir, the tension of the spring ber between said faces-arid at theirperiph eries, said member having the opposite side shaped to conform to the curvatureof sai( faces. i Y

.In a sound reproducer7 a diaphragm, i stylus bar mounted torock and having i vibratin f arm secured to saiddiaphragm means for adjusting said bar, andpneu matic cushioning' means for resistingtht ii'iovement of said bar. I In a sound reproducer, a diaphragm a stylus bar mounted to rock and having a vibrating arin, said stylus bar having a second arm, a bracket adapted to embrace said second arm near the end thereof, and cush-Y ioningr means between said second arm and said bracket.

7.*In a sound reproducer.y a diaphragm, a stylus bar adjustably mounted to rock and having a vibrating arm secured to said diaphragm, said stylus bar having a second arm, a bracket eniliiracing said second arm near the end thereof, said bracket and said arm having recesses. and cushioning means seated in saidv recesses of said second arm and said bracket, said second arm. being Y formed to hold resilient means adapted to `be removably secured to said bracket.

8. In a sound reproducer, a stylus bar having a recess adapted to receive a needle point, and a second recess transverse of said first recess, a member carried in said second recess and movable transversely of said first recess, said member having portions projecting from said stylus bar at the ends 'of said second recess and being provided with a notch adapted to grip the needle point, the projecting portions of said member being constricted whereby shoulders are formed, said second recess having a shoulder, re silient means in said second recess between said shoulder thereof and one of said slioulders of said member. and serving to hold `said member in a position such that said notch is normally displaced with respect to said recess. and means engaging the other of said shoulders of said member to limit the projection of said member from said second recess.`

Inftestiinony whereof I have signed my name to this specification in the presence of tivo subscribing'witnesses. i

WILLIAM ALBERT CHAPM A N.

litnesses z K H. C. STF..-\nu.\x, -G. lV. Parfums. 

